weeks.] PALEONTOLOGY, PETROLOGY, AND MINERALOGY, 1904. 119 
u. 
CJdden (J. A.). 
1. The geology of the Shafter silver-mine district, Presidio County, 
Texas. 
Tex. Univ. Min. Surv., Bull. no. 8, 60 pp., 11 figs., 2 pis., 1904. 
Describes the physiographic features briefly and in detail the occurrence, 
character, and geologic relations of Carboniferous and Cretaceous strata, 
igneous rocks, and mineral deposits, mainly silver ores. 
Ulrich (Edward Oscar). 
1. Fossils and age of the Yakutat formation. Description of collec- 
tions made chiefly near Kadiak, Alaska. 
Harriman Alaska Expedition, vol. 4, pp. 125-146, 11 pis., 1904. 
Discusses the geologic age of the Yakutat formation from the evidence of its 
fossils and gives systematic descriptions of these. 
2. Determination and correlation of formations [of northern Arkansas], 
U. S. Geol. Surv., Professional Paper no. 24, pp. 90-113, 1904. 
Discusses the occurrence, character, geologic relations, and correlation of 
Ordovician, Silurian, Devonian, and Carboniferous formations of northern 
Arkansas. 
3. Systematic paleontology of the Miocene deposits of Maryland: 
Hydrozoa. 
Md. Geol. Surv., Miocene, pp. 433-438, 1 pi., 1904. 
Ulrich (Edward Oscar) and Bassler (Ray S.). 
1. A revision of the Paleozoic bryozoa. Part I. On genera and spe- 
cies of Ctenostomata. 
Smith. Misc. Coll., vol. 45 (Quart. Issue, vol. 1, pts. 3 and 4), pp. 256-294, 4 pis., 
2 figs., 1904. 
2. A revision of the Paleozoic bryozoa. Part II. On genera and 
species of Trepostomata. 
Smith. Misc. Coll., vol. 47 (Quart. Issue, vol. 2, no. 1), pp. 15-55, 9 pis., 1904. 
3. Systematic paleontology of the Miocene deposits of Maryland: 
Ostracoda. 
Md. Geol. Surv., Miocene, pp. 98-130, 4 pis., 1904. 
4. Systematic paleontology of the Miocene deposits of Maryland: 
Bryozoa. 
Md. Geol. Surv., Miocene, pp. 404-429, 10 pis., 1904. 
United States Geological Survey. 
1. The United States Geological Survey, its origin, development, 
organization, and operations. 
U. S. Geol. Surv., Bull. no. 227, 205 pp., 9 pis., 5 figs., 1904. 
Describes the organization and work of the U. S^ Geological Survey and gives 
a full list of its publications. 
